Transmission or pipe systems usually include internally threaded connecting elements. The threads are often designed to either seal internal pressures to prevent leakage or retain mechanical components.
Pipes transporting gas, water, or some other substance usually contain connecting components in which the threads are tapered, decreasing in size from the pipe opening. The threads are tapered to provide a very tight fit which will provide a mechanical seal to prevent leakage. On the other hand, pipes, machine threads or the like whose primary function is to retain mechanical components are generally not tapered, the size of the threading is consistent throughout.
It is often necessary to clean or restore worn, irregular or defective machine threading. Devices exist which will cut new threads into worn, or irregular threading, but these devices modify the size and diameter of the original threading and actually remove the original threaded material. Since the original threaded material is removed, the original connecting components are rendered useless, and therefore these devices are not effective for merely removing corrosion and dirt from threads with the intent of reassembling the original connecting components.
In contrast to thread cutting devices, thread cleaning or chasing devices simply remove corrosion and dirt while maintaining the original integrity of the threading so that new oversized components are not required upon reassembly. Available chasing devices usually require disassembly of any components protruding from the casing which usually entails hours of expensive labor.
U.S. Pat. Nos. 876,964 and 4,121,486 describe valve or thread restoring devices which cut new threads for worn, irregular or defective valves. Since both of these devices cut into the original threading, they are not effective as chasing devices. Further, U.S. Pat. No. 4,121,486 is particularly unsuitable as a chaser since the device thread diameter is controlled by manually gripping levers, so it is impossible to control the exact size of the thread, and the tool will inevitably cut into the original threads to some degree.
The subject invention is designed to provide a simple and quick method of removing dirt and corrosion while leaving the integrity of the existing threads intact. It does not have the ability to recut threads. It provides a quick method of chasing since both ends of the device are open and it can be used without removing components from the machine casing eliminating the necessity of disassembling parts protruding from the machine casing. U.S. Pat. No. 2,567,480 is an example of a thread cleaning device which is only open on one end and would require complete disassembly and removal of any objects protruding from the threaded casing. The subject invention provides a simple method of chasing since a basic spanner wrench is used to rotate the chaser within the threaded casing to accomplish removal of the dirt and corrosion.
The subject invention is extremely pertinent to the marine industry where mechanical components which are not contained within the hull, but are constantly exposed to the water, are susceptible to corrosion and dirt. For example, subject invention could clean internal sterndrive gear threading without removing the propulsion unit.